In an evolved universal terrestrial radio access network (E-UTRAN), user equipment (UE) requests a resource from a network side device, and performs uplink data transmission by using a time frequency resource designated by the network side device.
The UE requests a resource from the network side device in the following manner: The UE reports, to the network side device, a buffer status report (BSR) used to reflect an amount of data to be transmitted by the UE. The network side device designates, for the UE according to the BSR reported by the UE, a time frequency resource used for uplink data transmission.
Currently, UE triggers, by using a trigger mechanism, reporting a BSR to request a network side device to allocate a resource. Specifically, when data on a logical channel with a higher priority for the UE enters a buffering queue of the UE, when an uplink data buffer of the UE is empty and new data is coming, or when a retransmission BSR timer (retxBSR-Timer) expires and data on a logical channel needs to be sent, the UE sends a regular BSR to the network side device. After the UE already allocates an uplink resource, when a size of a padding part is sufficient to accommodate BSR reporting information, the UE sends a padding BSR to the network side device. When a periodic BSR timer (periodicBSR-Timer) expires, the UE sends a periodic BSR to the network side device.
With evolution of wireless communications technologies, many services have a relatively high delay requirement. If the foregoing resource request manner continues to be used, and a BSR sending condition defined by a trigger mechanism is not satisfied when the UE receives service data that has a high delay requirement, the UE cannot obtain an appropriate time frequency resource for sending the service data. Consequently, a data transmission delay is increased, and user experience is degraded.